Samantha Cameron is refusing to move into "cramped" Downing Street until September.

This break with tradition by the Prime Minister's wife means the cost to taxpayers of providing security at her smart London home for four months could hit £1million.

And the price tag makes a mockery of her husband's public show of cutting spending by doing without police outriders and walking from No10 to the Commons.

Mrs Cameron, who is six months pregnant, has been dragging her heels since Mr Cameron became PM last week.

Her decision to snub protocol, at least until their baby is born, has raised both hackles and security fears. A retired Scotland Yard security chief said: "They are putting not just themselves but others at risk. Surely they should lead by example rather than insist on staying where it is not secure."

Chancellor George Osborne's wife Frances is also reluctant to leave her fivestorey Notting Hill townhouse for a Downing Street flat. Since Mr Cameron became PM the ring of steel round his £1.5million North Kensington house has infuriated neighbours.

There has been a permanent armed police presence, the road has been sealed off and resident and visitor parking bays have been suspended.

One neighbour said: "It's a pain in the neck. Why doesn't he move to No.10?" Police called a meeting for residents this week in a bid to quell mounting anger.